The present invention relates to a hybrid car, provided with an electric motor used to drive the vehicle, an internal combustion engine for power generation, and an auxiliary machinery, and also an operating method therefore. More particularly the present invention relates to a hybrid car being satisfactory in cruising range and power performances and an operating method for the hybrid car, in which the vehicle can enjoy an extended cruising range and improved power performances.
Recently, the regulations on exhaust gas from those vehicles which use an internal combustion engine as their drive source have been made more rigorous to tackle environmental pollution. In this respect, various new technologies have been developed. Electric cars, which use an electric motor as their drive source and produce no exhaust gas, should be ideal motor vehicles for reduction of the exhaust gas amount. Typical electric cars are designed so that a battery is used to supply the electric motor with electric power. Naturally, however, the available battery capacity for each vehicle is limited, so that the power performances are poorer and the cruising range is shorter than those of the vehicles which use the engine as the drive source. In order to make the electric cars more popular, these technical problems must be solved.
Hybrid cars, which are furnished with a generator, driven by means of an internal combustion engine, for battery charging, are believed to be promising modern electric cars which can enjoy an extended cruising range.
Like the typical electric cars, however, the hybrid cars are arranged so that auxiliary machineries, such as an air conditioner compressor, power-steering oil pump, negative-pressure pump for brake booster, etc., which are mounted in the vehicle, are driven by means of an auxiliary drive motor which is connected to the battery commonly used for the auxiliary drive motor and the vehicle drive motor. Accordingly, the available time for the battery is liable to be shortened so that the battery capacity becomes insufficient as the auxiliaries are driven. It is still difficult, therefore, for some hybrid cars, which are furnished with the motor-driven auxiliaries, to enjoy satisfactory cruising range and power performances. If the vehicle is furnished with the auxiliary drive motor, moreover, the vehicle is increased both in cost and in weight, and requires an additional space for this motor.